1. Field of the Invention
The invention relates to elongated instruments and preferably writing instruments and the like as well as to a clip assembly therefor which snap-locks onto the cap or body of the instrument to provide convenient attachment to wearing apparel or the like.
2. Description of the Prior Art
Various elongated instruments such as flashlights, tire gauges, small tools, such as pocket screwdrivers and the like, and, preferably, writing instruments such as pens, mechanical pencils, markers, and the like are well known in the art. Heretofore, the usual practice for constructing clips for such instruments consists of fabricating the clip as an integral part of the cap, either by producing them as a single molded entity or by devising a method whereby a separate clip is manufactured from either plastic or metal and is fixably secured in some manner to the body or cap of the instrument.
With respect to the use of integrally molded parts, the gripping tension in the longitudinal extension or arm of the clip dramatically decreases over time to the point where it can no longer maintain the instrument in a secure position. Furthermore, writing instruments made with both molded caps and bodies are highly energy intensive to produce due to the numerous molding operations necessary to produce the required parts.
Various alternate techniques have been utilized to secure the clip to the cap of such writing instruments. One system, disclosed in U.S. Pat No. 2,473,688 relates to a clip associated with a slotted cap for a writing instrument in which the arm of the clip is disposed exteriorly to the cap with two flanges disposed parallel to one another having an S-shaped spring between them and extending through the slot in the cap, which secures the clip within the interior of the cap. The arm of the clip is resilient in order to permit it to flex towards and away from the cap.
Another method of attachment is illustrated in U.S. Pat. No. 1,594,410 wherein a plate is located at the base of the clip which is provided with two lugs and two hook members which, upon being slid through pre-punched holes in the cap of a writing instrument, are flattened out against the interior of the cap in order to anchor the assembly in place. As the arm of the clip has a spring nature, the tongue end of the clip bears against the outer surface of the barrel of the writing instrument due to this tension.
U.S. Pat. No. 3,608,154 shows a different procedure for affixing a clip onto the cap of a writing instrument. This clip assembly, consisting of a base and a resilient shank, contains a projection upon the base which is inserted through an opening in the upper end of the cap and secured therein by a resilient retainer ring which is frictionally fitted within the cap. Finally, U.S. Pat. No. 3,453,694 to Hechtle relates to still another method of attachment wherein the serrated base plate of the clip is lockingly engaged into a serrated groove on the outer surface of the hollow cap of a writing instrument.
In the field of support clips for electrical conductors or tubes, U.S. Pat. No. 4,356,987 illustrates a clip consisting of two parallel shanks supported by a crosspiece. Each shank terminates in an outwardly facing, downwardly tapering surface for ease of insertion. Each shank also contains a rectangular groove at its midpoint which is open toward the outside and which, when the elastically interconnected shanks of the clip are forced together and pushed through a bore in the support, locks the clip onto the edges of the bore.
It is apparent from the foregoing that previous efforts at designing efficient clips for writing instruments suffer from several disadvantages. For example, the inexpensive plastic which is often used in such clips lacks sufficient resiliency. After numerous cycles of flexure toward and away from the body of the writing instrument, clips constructed in this manner fail to return to their original, unflexed position, thus losing their usefulness.
Subsequent attempts to design improved clips require either the insertion of a retaining device inside the cap of the writing instrument to anchor the clip into the cap or some alternate means by which projections upon the base of the clip could be bent back against the interior of the cap to hold the clip in place. The construction of writing devices using clips of this type requires more energy and/or a greater number of manufacturing steps.
We have discovered a new clip and system for attachment to elongated instruments such as writing instruments which avoids the aforementioned disadvantages of the prior art.